Spanish researchers claim they've turned a CD drive into a cheap lab scanner that can accurately detect tiny quantities of pesticide in samples placed on top of an ordinary CD. The scientists say the modified CD-ROM drive features two extra light sensors and can detect levels of pesticide as low as 0.02 micrograms per litre.
Biologists and chemists often detect and measure compounds of interest, such as disease pathogens in blood or pollutants in water, by triggering interactions between these compounds and known proteins and antibodies. These immunoassay tests produce further compounds that can then be measured accurately, typically using light.
However, the machines used for light detection are expensive, normally costing between 30,000 and 60,000 euros, says Angel Maquieira, of the Polytechnic University of Valencia, Spain.
Maquieira and colleagues found that an off-the-shelf CD drive can be modified to do the same job. While a laboratory machine has to precisely scan samples with light and record the results, a CD player uses similar precision to read the tiny pits that encode music or data on a disk.
"The main advantages of using a CD reader are versatility, simplicity, ease of operation, and portability for point-of-need applications," Maquieira told New Scientist.
The researchers say the device is slower than real lab scanners but a lot cheaper. More info at Newscientist.